UVA 439

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int d[8][2]={{1,2},{2,1},{-1,2},{-1,-2},{1,-2},{-2,-1},{-2,1},{2,-1}};
int q[100];
int dis[10][10];
int vis[10][10];
void bfs( int x, int y )
{
	int front, rear, nx, ny, u, i, v;
	u = x*8+y;
	front = rear = 0;
	vis[x][y] = 1;
	dis[x][y] = 0;
	q[front++] = u;
	while( front > rear )
	{
		u = q[rear++];
		x = u /8; y = u % 8;
		for( i = 0; i < 8; i++ )
		{
			 nx = x + d[i][0];
			 ny = y + d[i][1];
			 if( nx>= 0 && nx < 8 &&ny >=0 && ny < 8 && !vis[nx][ny] )
			 {
				 v = nx*8 + ny;
				 q[front++] = v;
				 vis[nx][ny] = 1;
				 dis[nx][ny] = dis[x][y] + 1;
			 }
		}
	}
}
int main()
{
	int x1, y1, x2, y2;
	char s1[10], s2[10];
	while( scanf( "%s%s", s1, s2 ) != EOF )
	{
		x1 = s1[0]-'a'; y1 = s1[1]-'0'-1;
		x2 = s2[0]-'a'; y2 = s2[1]-'0'-1;
		memset( dis, 0, sizeof(dis) );
		memset( vis, 0, sizeof(vis) );
		bfs( x1, y1 );
		printf( "To get from %s to %s takes %d knight moves.\n", s1, s2, dis[x2][y2] );
	}
	return 0;
}